Device for measuring dimensions of workpieces

ABSTRACT

There is disclosed a device for measuring dimensions of workpieces, particularly rod shaped workpieces. The device includes a supporting means for supporting and roughly aligning the workpieces, a measuring mean for detecting the length of the workpiece, and a control unit including memory means for storing the measured values. The measuring device of the present invention is characterized in that the measuring means (1, 103) is provided with a sensor means (6, 104) for detecting dimensions of a cross-section of the workpiece (1, 101).

TECHNICAL FIELD

The present invention relates to a device for measuring dimensions ofworkpieces, which device includes a supporting means for supporting androughly aligning the workpiece, a measuring means for detecting thelength of the workpiece, and a control unit including memory means forstoring the measured values.

BACKGROUND ART

DE 33 18 420 discloses a device for measuring the length of rods whichare stored within the scope of an automated stock management. In thisdevice the respective lengths of the rods are stored in a stockmanagement computer. Thus, a suitable workpiece, whose total lengthcorresponds to the individual pieces to be made, is chosen in anindependent manner with the aid of the stock management computer for asubsequent manufacturing order, for instance for processing in a sawingmachine. To determine the length of the rod, a length measuring devicesenses the distance of the front sides of the workpiece from a referencepoint. The length measuring device has a stop and a slide which isopposite to the stop at a distance and movable relative thereto forpushing the rod to be measured onto the stop. The resultant distance ofthe slide from the stop corresponds to the length of the workpiece to bemeasured and is stored in the stock management computer so that it isassigned to the respective workpiece.

It is however disadvantageous that the rod must be brought into adefined position for the measurement, namely into contact with the fixedstop, and a supporting means which supports the rod must at least permita displacement of the rod in the longitudinal direction and must bearranged accordingly. Moreover, with the known device it is not possibleto measure cross sections or to determine a straightness of the rod.Thus, on the one hand, the automated stock management cannot make adistinction between rods of full material, hollow profiles or corneredor round cross-sections, and on the other hand, excessively bent rodsmight be supplied to the manufacturing process so that required shapetolerance cannot be achieved with such rods, and when preset limitvalues are exceeded, the rods may cause damage during the storingprocess or when supplied to the cutting-off machine.

Furthermore, a device is known wherein a measuring roll presses againstthe rod and is rolled along the rod for determining the length of therod. At the same time, the setting height of the measuring roll isdetected via an NC axis and the thickness of the material is determined.This device, however, has the following disadvantages. First, it is onlythe height, but not the shape or width of the rod, that can bedetermined. Second, the length of the rod can only be determined withgreat tolerance due to different material surfaces, such as round orflat, smooth or scaled surfaces and also due to a rolling of themeasuring roll at the rod end during transition from the horizontalmovement into the vertical movement. A straightness of the rod can alsonot be determined with the known device. Moreover, in this device too,the rod must be pushed at one side against a stop, resulting in theabove-mentioned disadvantages.

DISCLOSURE OF INVENTION

It is the object of the present invention to improve a device of theabove-mentioned type in such a manner that the geometry of the workpiececan be determined in a sufficiently accurate manner to select aworkpiece from the stock for a specific manufacturing order.

In a device of the above-mentioned kind, this object is attainedaccording to the invention by the provision of a measuring meansprovided with a sensor means for detecting a cross-section. In anadvantageous embodiment, the measuring means is further provided with asensor means for detecting a straightness of the workpiece.

The device of the invention is especially characterized in that the bestsuited workpiece can respectively be chosen with increaseddifferentiation for a manufacturing order to be executed within thescope of an automated stock management. Since the workpiece to be storedcan be classified not only with respect to their length, but can also bedistinguished with respect to their cross section and theirstraightness, manufacturing orders can be executed substantiallyindependently and with increased efficiency. The measured values whichare stored in the memory means in addition to the workpiece length, forinstance height, width, round cross-section or square cross-section orstraightness of the workpiece and also wall thickness in the case ofhollow bodies, enable the control unit to select a suitable workpiecefrom the stock and to supply it to the processing machine. Thus possiblefaulty data input by the operator will be recognized, and input of suchdata by the operator can be dispensed with entirely.

An advantageous development of the invention is that the sensor means isprovided with a measuring head slidably supported on a guiding deviceand drivable by a driving means, and a path measuring device is providedfor detecting the position of the measuring head relative to the guidingdevice. As long as the workpiece rests on the supporting means, themeasuring head is moved along the surfaces of the workpiece to bemeasured. The path measuring device senses the distance traveled by themeasuring head during scanning, thereby determining the respectivegeometrical data, such as workpiece length, width, or height.

In an advantageous embodiment, the measuring head is slidably guided ona longitudinal guidance extending in the longitudinal direction of thesupporting means and in a plane perpendicular to the longitudinalguidance. The measuring head can thus be guided past the lateral surfaceof the workpiece, on the one hand, for determining the length orstraightness of the workpiece in the longitudinal direction of theworkpiece, and past the front surfaces thereof, on the other hand, fordetermining the cross-section of the workpiece in directionsperpendicular to the longitudinal direction.

In the advantageous development, the workpiece has just to be alignedroughly in its orientation for being measured and an exact positioningis not required. The sensor means preferably includes a laser sensor.The workpiece can thus be scanned without contact. The laser sensor inparticular detects the distance between the measuring head and a surfaceof an object by which the laser beam is reflected therefrom. When themeasuring head is guided past the front surface of the workpiece or thelateral surface thereof, a first signal change which corresponds to abeginning of the workpiece contour takes place upon impingement of thelaser beam on the material. Like the subsequent signal changes, thesignal change is used during continued travel past the surface of thematerial for determining the distance of the material surface from themeasuring head and for determining the geometrical dimensions of theworkpiece.

In accordance with an advantageous embodiment the control unit includesan evaluating unit for linking measured path data of the path measuringdevice with laser beam measuring signals of the laser sensor todetermine the cross-sectional dimensions and straightness of theworkpiece.

An advantageous embodiment of the invention is also given by the factthat there is provided with two linear guidances in the planeperpendicular to the longitudinal guidance. A first one of the twolinear guidance is preferably supported slidably at least in thelongitudinal direction on the longitudinal guidance, and a second onecarrying the measuring head is supported on the first linear guidancefor sliding in two directions in the plane perpendicular to thelongitudinal guidance. Alternatively, the measuring head is slidablyguided on the second linear guidance, which is slidably guided on thefirst linear guidance. Further, the first linear guidance may beslidably guided on the longitudinal guidance in the plane perpendicularto the longitudinal direction as well as slidably guided in thelongitudinal direction on the longitudinal guidance.

The measuring head can thus be moved in any desired direction ifindividual driving means for driving linear guidances arecorrespondingly operated. In particular, the measuring head of the lasersensor is movable in different directions in a plane perpendicular tothe longitudinal direction of the workpiece in order to detect thecross-sectional geometry of the workpiece in accordance with a suitablealgorithm in several scanning operations. In the scanning operations,first and last signal changes are respectively measured and localized.Apart from the determination of the cross-sectional dimensions, such asheight and width, a distinction can be made between round material andflat material or full profiles and hollow profiles. Optionally, adetermination of the wall thicknesses of the workpiece can also be made.The determination of the cross-section of the workpiece with complicatedcross-sectional geometries is also possible by comparing the measuredvalues with data from a profiled material data base. After the frontsurface of the workpiece has been scanned, the whole cross slide ismoved along the longitudinal guidance to scan the lateral surface of theworkpiece in the longitudinal direction thereof with the aid of thelaser sensor so as to determine the length of the workpiece on the onehand and to determine straightness and inclined position of theworkpiece on the other hand.

In an especially advantageous embodiment of the invention, the pathmeasuring device is provided with a first path measuring sensor fordetecting the position of the first linear guidance relative to thelongitudinal guidance, a second path measuring sensor for detecting theposition of the second linear guidance relative to the first linearguidance and/or a third path measuring sensor for detecting the positionof the measuring head relative to the second linear guidance. As aresult, the positions where the signal changes occur can exactly belocated, and the length of displacement within which a signal changetakes place can be determined exactly, so that the geometrical dataderived therefrom can precisely be calculated. Further, it is possibleto measure the distance of the measuring head from the material surfaceat fixed intervals when the cross slide slides along the longitudinalguidance for scanning the lateral surface of the workpiece in thelongitudinal direction. The respectively measured laser data and theassociated measured path data are linked by the control unit forcalculating straightness and inclined position of the workpiece on thesupporting means.

An advantageous embodiment of the invention is that the driving means isprovided with a toothed belt drive to which an encoder is coupled. Theposition of the measuring head can be determined by the encoder in avery exact manner, so that the measurement of dimensions and/or shape ofa workpiece is virtually faultless.

A preferred development of the invention is characterized in that apivotal arm guidance with at least two pivotal arms is provided forguiding the measuring head in the plane perpendicular to thelongitudinal direction of the workpiece. The pivotal arm guidance isslidably supported on the longitudinal guidance in the longitudinaldirection. A first pivotal arm is pivotal relative to the longitudinalguidance about a first axis parallel to the longitudinal direction, anda second pivotal arm is pivotal relative to the first pivotal arm abouta second axis also parallel to the longitudinal direction. In a waysimilar to that of the above-mentioned cross slide guidance, such apivotal arm guidance can guide the measuring head in any desireddirections past the front surface of the workpiece to detect thecontours of the workpiece. The pivotal arm guidance is moved along thelongitudinal guidance after the two pivotal arms have brought themeasuring head into a suitable position for measuring the length and fordetermining the straightness of the workpiece. In this way, themeasuring head is moved along the lateral surface of the workpiece inthe longitudinal direction thereof. By analogy with a pivotal arm robot,the two pivotal arms are driven to pivot about individual pivot axes.The position of the measuring head is sensed by sensors for sensing theangular positions of the pivotal arms relative to each other.

In an advantageous embodiment of the invention, a swinging means isprovided for swinging the measuring head relative to the guiding device.With this swinging means, when both the front surface and the lateralsurface of a workpiece are to be scanned, the measuring head of thesensor means is always brought into an angular position perpendicular tothe surface member to be scanned, so that a laser beam reflected by thesurface can be detected optimally. The guiding device can be constructedin a very simple manner owing to the swinging means. This is because theguiding device has only to move the measuring head of the sensor meansto the locations in the space and because the orientation, i.e. theangular position of the measuring head relative to the workpiece, isadjusted by the swinging means.

With the swinging means, it is easily possible to scan the front surfaceand the lateral surface of the workpiece with a single sensor means or asingle measuring head. However, it is also possible to provide two orgenerally several measuring heads on the guiding device so as to scanthe differently oriented workpiece surfaces with different measuringheads.

In accordance with a preferred embodiment of the invention the measuringhead is swingable about two axes. The measuring head is therebyswingable, for complicated workpiece contours, into positionsrespectively perpendicular to the workpiece surface sections to bescanned, so that the workpiece can be scanned along several lines.

In a preferred embodiment the swinging means is provided with two seriesconnected swinging members which are each swingable about a swingingaxis by 90° between two positions. The swinging members are disposed insuch a manner that the swinging axes of the two swinging members areperpendicular to each other. Such a series connection permits the use ofstandardized and therefore inexpensive swinging means, such ascompressed-air adjusting means which offer adequate accuracy at a lowprice.

In a further advantageous embodiment of the invention, first and secondmeasuring means are provided for detecting the distance of a first frontsurface and an opposite second front surface of the workpiece, which issupported on the supporting means, from a reference point. In thisembodiment, the workpiece has also just to be aligned roughly in itsorientation and an exact repositioning can be dispensed with formeasuring the workpiece, in particular, for detecting the workpiecelength. That is, this embodiment is especially characterized in that anexact positioning of the workpiece is unnecessary, which is especiallyof advantage in the case of bulky or heavy workpieces. Thus thesupporting means must just be designed for a rough alignment of theworkpiece.

In an advantageous development, a measuring head of the laser measuringmeans is disposed on a measuring carriage slidably supported on aguidance and drivable by a driving means in a direction parallel to thefront surface of the workpiece. A path measuring device is provided fordetecting the position of the measuring head during a laser scanningoperation of the front surface of the workpiece. The measuring head isguided past the front surface of the workpiece. When the laser beamimpinges on the material, there will be a first signal change. Like thesubsequent signal changes, this signal change is evaluated by themeasuring means and the control logic, respectively. Thus, duringcontinued travel past the front side of the material the distance of thefront surface of the material from a reference point is determined andthe cross-sectional dimensions of the workpiece are detected.

The guidance is preferably swingable about an axis which issubstantially in parallel with the intersection axis of a supportingsurface and a bearing surface of the supporting means. Thus, in a firstposition of the guidance, the measuring carriage is drivable in parallelwith a front surface diagonal of the workpiece supported on thesupporting means, and, in a second position of the guidance, in parallelwith the supporting surface of the supporting means. The first scanningoperation along the front surface diagonal enables the control unit tomake a distinction between round material and flat material. In case ofa round material, the corners are not filled with material with respectto the supporting and bearing surfaces of the supporting means, incontrast to the case of the flat material. This means that, when themeasuring head is guided by in the first position of the guidance, afirst signal change will only take place at a certain distance from theintersection axis of the supporting surface and the bearing surface ofthe supporting means. This fact is exploited by the control unit to makea distinction between round material and flat material.

In the second position of the guidance in parallel with the supportingsurface of the supporting means, the measuring carriage is guided withthe laser measuring head past the front surface for determining thewidth and possibly the wall thickness of the workpiece. As regardshollow or profiled material, the measured values can be compared by thecontrol unit with samples in a profiled material data base in the memorymeans, whereby the profile can be defined in an exact manner.

The control unit preferably includes an evaluating unit for linkingmeasured path data of the path measuring device with laser beammeasuring signals of the laser measuring means for determining thecross-sectional dimensions of the workpiece. As a result, changes in thesignal level during scanning upon impingement of the laser measuringbeam on the material can be localized in combination with measured pathdata of the path measuring device, whereby the cross sections of theworkpieces can be recognized by the above-mentioned way.

In another advantageous embodiment of the invention, the sensor meansincludes a laser measuring means and a deflector device for deflecting alaser measuring beam for scanning the front surface of the workpiece.The laser measuring means need therefore not be arranged so as to beslidably supported on a guidance, but it is sufficient to arrange thelaser measuring means in a stationary position, since the front surfaceof the workpiece is scanned by deflection of the laser measuring beam.

An advantageous development of the invention is that the secondmeasuring means is provided with a tactile sensor disposed on ameasuring carriage, which is supported slidably substantially inparallel with the intersection axis of the supporting surface and thebearing surface of the supporting means. A driving means is provided fordriving the measuring carriage towards the front surface of theworkpiece and a path measuring means is provided for detecting theposition of the measuring carriage. The tactile sensor may for instancebe a mechanical probe in combination with a switching element or a lightbarrier. The measuring carriage together with the tactile sensorarranged thereon is moved towards the second front surface of theworkpiece to such an extent that a signal change will take place in thesensor upon impact on the second front surface. The position of themeasuring carriage and thus the distance of the second front surface ofthe workpiece from a reference point can be detected by the pathmeasuring means.

The driving means preferably includes a toothed belt drive to which anencoder is coupled for path measurement. As already explained above, thepath is thus measured with a very high accuracy, as a result of whichthe length of the workpiece is also determined precisely.

An advantageous embodiment of the invention consists in that the secondmeasuring means includes a laser measuring apparatus having a lasermeasuring head or an ultrasonic measuring apparatus having an ultrasonicmeasuring head disposed at a fixed distance from a reference point. Thisis of advantage for the reason that the device can be of a very simpleand therefore of inexpensive type.

The second measuring means advantageously includes a guidance, on whichthe laser or ultrasonic measuring head is slidably supported forscanning the second front surface of the workpiece in a directionperpendicular to the intersection axis of the supporting surface and thebearing surface of the supporting means. During displacement of themeasuring head a signal change takes place when the laser beam impingeson the second front surface of the workpiece, whereby the distance ofthe second front surface from a reference point is determined by thecontrol unit.

However, scanning of the second front surface of the workpiece throughthe laser measuring beam can also be performed with a deflector devicein a manner similar to that with the above-explained deflector devicefor the laser measuring means of the first measuring means.

Another preferred embodiment of the invention is that the supportingmeans is a conveyor means for cross-conveying the workpieces. Theconveying means is provided with conveying chain belts with pushingbolts attached thereto. The conveying chain belts forms the supportingsurface and the pushing bolts forms the bearing surface. This is ofparticular advantage, since the process for measuring workpieces isdirectly integrated into the conveying process of the rods between stockand processing machine. Hence, a separate conveying step for measuringthe workpieces is unnecessary, so that storage and removal of rod shapedworkpieces can be performed rapidly and economically.

In another advantageous embodiment of the invention, a first guidance,on which the measuring head is supported, is slidably supported on asecond guidance. With this arrangement, in different positions of thefirst guidance on the second guidance, the measuring carriage is movableat different distances from a supporting surface of the supportingmeans. A first scanning operation along the supporting surface isperformed at that predetermined distance from the supporting surfacewhich permits a signal change in the measuring head independently of thedimensions of the workpiece. Independently of the cross section of theworkpiece, the control unit can determine the central perpendicular ofthe front surface of the workpiece on the basis of the first and lastsignal changes that take place when the measuring head is guided by.

The measuring carriage can also be driven in a direction perpendicularto the supporting surface by displacing the first guidance along thesecond guidance. This makes it possible to detect the height of theworkpiece in a second scanning operation, in particular along thepreviously determined central perpendicular. This dimension correspondsto the diameter in case of round material. Moreover, a comparisonbetween the measured results of the first and second scanning operationspermit the control unit to make a distinction between round material andflat material. If the distance of the measuring points at which thefirst and last signal changes take place during the first scanningoperation is greater or equal to the height, this means a flat material,since flat material is always supported with its broad side on thesupporting surface.

With complicated workpiece geometries, the measuring head is guidedseveral times along the front surface of the workpiece at differentdistances in parallel with the supporting surface and in directionsperpendicular thereto, so that the measured values can be compared bythe control unit with samples in a profiled material data base in thememory means, whereby the profile can be defined in an exact manner.

The present invention shall now be explained in more detail withreference to embodiments and associated drawings, in which:

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a front overall view of a device for measuring dimensions ofworkpieces according to a first embodiment of the invention;

FIG. 2 is a lateral view of a portion of the first measuring means,indicated by an arrow II in FIG. 1;

FIG. 3 is a lateral view of the portion of the first measuring means asshown in FIG. 2, in three differently swung positions;

FIG. 4 is a detailed view of a conveying means indicated by an arrow IVin FIG. 1, the conveying means including a chain belt and pushing bolts,and a workpiece resting on the chain belt in contact with a pushingbolt;

FIG. 5 is a graphic representation illustrating the relationship betweena signal level of a laser measuring beam of a laser measuring apparatusand the position of the laser measuring apparatus relative to a frontsurface of a workpiece for different workpiece cross-sections at twodifferent swinging positions of the first measuring means according tothe embodiment of FIG. 1;

FIG. 6 is a partial top view of a device for measuring dimensions ofworkpieces according to a second embodiment of the invention, with asecond measuring means alternatively including a laser measuringapparatus or an ultrasonic measuring apparatus;

FIG. 7 is a lateral view of a portion of the second embodiment,indicated by an arrow VII in FIG. 6, a conveying means having a chainbelt and pushing bolts, and a workpiece being supported on the chainbelt in contact with a pushing bolt;

FIG. 8 is a lateral view of a second measuring means in differentswinging positions according to the embodiment of FIG. 7, the measuringmeans being shown in a first position in parallel with a supportingsurface, in a second position in parallel with a front surface diagonalof the workpiece, and in a third position in parallel with a bearingsurface;

FIG. 9 is a top overall view of a device for measuring dimensions ofworkpieces according to a third embodiment of the invention;

FIG. 10 is a lateral view of a portion of first measuring means,indicated by arrow X in FIG. 9, the measuring means including anassociated sensor means and first and second guidances;

FIG. 11 is an enlarged lateral view of the first and second guidancesshown in FIG. 10;

FIG. 12 is a graphic representation illustrating the relationshipbetween a signal level of a laser measuring beam of a laser measuringapparatus and the position of the laser measuring apparatus relative toa front surface of a workpiece for different workpiece cross-sectionsand different positions of the first guidance according to theembodiment of FIG. 9;

FIG. 13 is a front overall view of a device for measuring workpiecesaccording to a fourth embodiment of the invention;

FIG. 14 is a lateral view of the device including a sensor means whichis disposed on a guiding device shown in different positions, inaccordance with the embodiment of the invention according to FIG. 13;

FIG. 15 is a detailed lateral view of a swinging means for swinging ameasuring head of the sensor means according to the embodiment of FIG.13;

FIG. 16 is a detailed view, similar to FIG. 15, of the swinging meansfor swinging the measuring head of the sensor means in another swingingposition of the measuring head according to the embodiment of FIG. 13;

FIGS. 17A, 17B, and 17C are partial views of another swinging means forswinging the measuring head of the sensor means according to theembodiment of the invention in FIG. 13, the swinging means being shownin different positions in a lateral view and front view, respectively;

FIG. 18 is a diagrammatic and perspective overall view for illustratingthe kinematics of the guiding device according to the embodiment of FIG.13;

FIG. 19 is a diagrammatic and perspective view for illustrating thekinematics of a guiding device of a device for measuring workpieces inaccordance with a fifth embodiment of the invention;

FIG. 20 is a graphic representation illustrating the relationshipbetween a signal level of a laser measuring beam of a laser sensor andthe position of the laser sensor relative to a front surface of aworkpiece for different workpiece cross-sections and for two differentpositions of the laser sensor according to the embodiments of FIGS. 13and 19;

FIG. 21 is a graphic representation, similar to FIG. 20, illustratingthe relationship between the signal level of the laser measuring beam ofthe laser sensor and the position of the laser sensor during scanning ofthe workpiece in the longitudinal direction thereof for two differentpositions of the laser sensor according to the embodiments of FIGS. 13and 19.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a first embodiment of a device for measuring sizes ofworkpieces. A supporting means 12 forms part of a cross conveying means(not shown in more detail). As becomes apparent from FIG. 4, the crossconveying means includes conveying chain belts 23 which are driven by apinion 28 and a drive (not shown) and form a supporting surface 11 onwhich a workpiece 5 is supported. The conveying chain belts 23 havepushing bolts 25 which are attached thereto and form a bearing surface26. On the surface 26, the workpieces 5 are roughly aligned during crossconveyance on the cross conveying means. The conveying chain belts 23and the pushing bolts 25 are closely arranged for short workpieces, suchas short rods or remaining rods, towards one side of the cross conveyingmeans in the longitudinal direction of the workpiece and have anincreasing distance to the other side of the cross conveying means.

The cross conveying means is part of a conveyor system by whichworkpieces, in particular rods, are conveyed from a storage place to aprocessing machine, in particular a saw. After having been processed,the workpieces are conveyed back to the storage place at least partly,i.e. the remaining pieces which were cut off.

At the sides of the supporting means 12, a first measuring means 1 and asecond measuring means 2 are arranged outside of the supporting area.The first measuring means 1 is immovable relative to the longitudinalaxis of workpiece 5 while the second measuring means 2 is arranged on ameasuring carriage 14 which is displaceable on a measuring carriageguidance 27 substantially in parallel with the longitudinal axis ofworkpiece 5.

The first measuring means 1 and the second measuring means 2 detect thedistance of a front surface (a first front surface) 3 and a rear surface(a second front surface) 4, respectively, of workpiece 5 from areference point. The distances are processed in a control unit, wherebylength L0 of workpiece 5 is calculated. To detect the distance of thefront surface 3 and of the rear surface 4 from a reference point,workpiece 5 need not be pushed against a fixed stop or the like, so thatthe workpiece 5 on the supporting means 12 can be in any desiredposition in the longitudinal direction and there is Just a roughalignment on the pushing bolts 25.

The first measuring means 1 includes a sensor means 6 which is movablysupported on a guidance 9 (FIG. 2). As shown in FIGS. 2 and 3, thesensor means 6 is arranged on a laser measuring means whose measuringhead 7 is arranged on a measuring carriage 8 which is attached to atoothed belt drive 17. The measuring head 7 may include a conventionallaser rangefinder. The toothed belt drive 17 is a part of a drivingmeans 13 by which the measuring head 7 of the laser measuring means ismoved along guidance 9. The guidance 9 is substantially arranged at aright angle relative to the alignment of the pushing bolts 25 ofsupporting means 12 (i.e. at a right angle relative to the thelongitudinal direction of the workpiece). Thus measuring head 7 of thelaser measuring means is movable in parallel with the front surface 3 ofworkpiece 5. To detect the distance of front surface 3 from thereference point, the measuring head 7 is guided past the front surface 3in such a manner that upon impingement of a laser measuring beam onworkpiece 5 there will be a signal change which will be evaluated by thecontrol unit. During travel of the measuring head 7 past the frontsurface 3 of workpiece 5, the distance of the front surface 3 from thereference point is determined by the control unit.

An important aspect of the present invention is the possibility ofdetecting the cross-sectional dimensions of workpiece 5. To this end,guidance 9, along which the measuring carriage 8 is movable with themeasuring head 7 attached thereto, is rotatably supported on a frame 29of the device. The guidance 9 is swingable about an axis which issubstantially in parallel with the intersection axis of the supportingsurface 11 formed by the chain belts 23 and the bearing surface 26 whichis defined by the pushing bolts 25 (FIG. 3). That is, it is swingable insuch a manner that the measuring head 7 is movable in a first angularposition of the swingable guidance 9 along a front surface diagonal ofworkpiece 5, which rests on the supporting means 12. In particular, itis substantially movable at a 45° angle relative to the supportingsurface 11, as is apparent from FIG. 3. During displacement of themeasuring head 7 along the guidance 9 the laser measuring beam sweepsover the corner portion between the supporting surface 11 and thebearing surface 26 in this angular position of guidance 9, whereby thecontrol unit can make a distinction between round and flat materials inthe workpiece in accordance with an evaluating logic stored in thememory means, as shown in FIG. 5. In contrast to flat material, thecorner portions are not filled with material in the case of a roundmaterial at the corner portion between the supporting surface 11 and thebearing surface 26.

To see at which point a workpiece contour is present where uponimpingement of the laser measuring beam on the workpiece a first or lastsignal change will take place, or in a more general manner a change inthe signal level, the driving means 13 which effects the displacement ofthe measuring carriage 8 with the measuring head 7 attached thereto isprovided with a path measuring means 10 (FIG. 1). The path measuringmeans 10 includes an encoder coupled to the toothed belt drive 17 fornumerical path measurement. Thus in the control unit the measured pathdata which are detected by the path measuring means 10 can be linkedwith the laser beam measuring signals of the laser measuring means fordetermining the cross-sectional dimensions of workpiece 6.

As shown in FIG. 5, a path "a" between the surface of the workpiece andthe intersection axis of the supporting surface 11 and the bearingsurface 26, in which no signal change takes place in the measuring head7, is an indicator on the basis of which the evaluating logic of thecontrol unit can recognize whether workpiece 5 is a round or flatmaterial. If workpiece 5 is a round material, the length of path "a" isgreater than zero. By contrast with a flat material, the first signalchange takes place directly, or in accordance with an admissiblematerial curvature slightly above the supporting surface 11. The pathmeasuring means 10 thus senses a path "a" which is approximately zero.The path of displacement L is sensed by the path measuring means 10 whenthe next signal change takes place. The path L yields the materialheight H upon conversion of the corresponding angular position which, asalready stated, is about 45° relative to the supporting surface 11. Inthe case of a hollow material, the wall thickness "t" is also measured.

In case workpiece 5 is a flat material, guidance 9 is swung fordetermining the workpiece width W into a second angular position whichis in parallel with the supporting surface 11. In this angular position,the measuring head 7 of the laser measuring means can be displaced inparallel with the supporting surface 11. The distance of displacement ofthe measuring carriage 8 where a signal change takes place in measuringhead 7 is sensed by the path measuring means 10 and by the control unit,as a workpiece width W.

Likewise, it is possible to swing guidance 9 into a third angularposition substantially in parallel with the bearing surface 26 so as tomeasure the workpiece height H in a corresponding manner directly or tocheck the calculation on the basis of the measured data which wereobtained in a first position of guidance 9 during displacement ofmeasuring carriage 8.

When workpiece 5 is a hollow and profiled material, the laser beammeasuring signals are compared by the control unit, in combination withthe measured path data, with pattern data stored in the memory means inthe form of a profiled material data base. The respective profile ofworkpiece 5 can thereby be defined in an exact manner.

If workpiece 5 is a round material, it is normally sufficient to guidethe measuring head 7 once past the front surface 8 in the first positionof guidance 9 in parallel with a front surface diagonal. Due to specificcircumstances, such as an excessively curved workpiece 5 or an incorrectsupport of workpiece 5 on the supporting surface 11 or an insufficientalignment of workpiece 5 on supporting surface 26, the control unit mayerroneously assume the presence of flat material. However this erroneousassumption induces a further measurement of the workpiece width W bydisplacing measuring carriage 8 in the second position of guidance 9 inparallel with supporting surface 11, and this further measurement willpossibly lead to a correction.

The second measuring means 2 which is arranged at the side opposite tothe first measuring means 1 includes a tactile sensor 18, as can be seenin FIG. 1, which is disposed on a measuring carriage 14. As shown inFIG. 4, measuring carriage 14 includes a slide 30 which is movablysupported on measuring carriage guidance 27, as well as an arm 31 whichis rigidly secured with its one end to slide 30. The other end of thearm 31 has the tactile sensor 18 disposed thereon. The measuringcarriage guidance 27 extends in parallel with the intersection axis ofthe supporting surface 11 and the bearing surface 26, so that themeasuring carriage 14 of the second measuring means 2 is movable inparallel with the longitudinal axis of workpiece 5 which rests on thesupporting means 12. A driving means 15 is provided for displacingmeasuring carriage 14, the respective position of measuring carriage 14being sensed by a path measuring means 16. The driving means 15 includesa toothed belt drive which has an encoder coupled thereto for directpath measurement. Thus the measuring carriage 14 can be moved exactlyand its respective position can be detected accurately.

To detect the distance of the rear surface 4 from a reference point,which is used by the control unit for calculating length L0 of workpiece5 together with the distance of the front surface 3 from the referencepoint, the guidance 27 toward the rear surface 4 of workpiece 5 untiltactile sensor 18 will supply a signal upon impact on the rear surface4. The reference points for the first and second measuring means 1, 2may be the same, or may be different from each other.

To enable the tactile sensor 18 to hit on the rear surface 4 ofworkpiece 5 in the case of different workpiece sizes and differentworkpiece positions on the supporting means 12, a contact plate 32 whichis movably supported on arm 31 of measuring carriage 14 is provided onthe arm 31 between the tactile sensor 18 and the area in which workpiece5 is supported. Thus upon impact on the front surface 4 of workpiece 5the contact plate 32 is pushed onto the tactile sensor 18 attached tothe arm 31, so that tactile sensor 18 will supply a signal. A springelement 33 which biases the contact plate 32 into a position in whichthe tactile sensor 18 does not provide a signal is disposed betweencontact plate 32 and arm 31. Spring element 33 biases contact plate 32with a very slight force, so that upon impact of contact plate 32 on therear surface 4 of workpiece 5, workpiece 5 will not be displaced.

In this embodiment tactile sensor 18 is designed as a mechanical probein combination with a switching element, but a light barrier or the likemay also be used.

An advantage of this embodiment of the invention is the very largemeasuring range. For instance, rod lengths from 400 mm to 1,000 mm canbe detected.

FIGS. 6, 7, and 8 show a second embodiment of the present invention, inwhich essential parts of the first embodiment are similar. Thestructural members which resemble the first embodiment are provided withthe same reference numerals.

For instance, the device according to the second embodiment includes asupporting means 12, which forms part of a cross conveying means, havingconveying chain belts 23 which form a supporting surface 11, and pushingbolts 25 which form a bearing surface 26. First and second measuringmeans 1 and 2 are provided at both sides of the supporting means 12outside the supporting area in which workpiece 5 rests. The firstmeasuring means 1 corresponds to the first measuring means of theabove-described first embodiment, and serves to measure the distance ofthe front surface 3 of workpiece 5 from a reference point and to detectthe cross-sectional dimensions of workpiece 5.

The second measuring means 2 includes a laser measuring device 19 havinga laser measuring head 20 arranged at a fixed distance from a referencepoint. Like the laser measuring means of the first measuring means 1,the laser measuring head 20 of the second measuring means 2 is movablyarranged on a guidance 21 which is aligned at a right angle relative tothe bearing surface 26 which is defined by the pushing bolts 25. Thusthe laser measuring head 20 of the laser measuring apparatus 19 ismovable in parallel with the rear surface 4 of workpiece 5.

As can be seen in FIG. 7, when the laser measuring head 20 of the secondmeasuring means 2 is guided past the rear surface 4 of workpiece 5 in adirection perpendicular to the longitudinal axis of workpiece 5, asignal change takes place in the laser measuring apparatus 19 due toreflection of the laser measuring beam by the workpiece S, whereby thedistance of the rear surface 4 from the reference point is detected.

Instead of the laser measuring apparatus 19, an ultrasonic measuringapparatus (Sonarbero) can be used with an ultrasonic measuring head 24.

An shown in FIG. 8, guidance 21 is swingable about an axis which issubstantially in parallel with the intersection axis of the bearingsurface 26 with the supporting surface 11 of the supporting means 12.Thus the rear surface 4 of workpiece 5 can be scanned in differentpositions like with the first measuring means 1, and the cross-sectionaldimensions of workpiece 5 can be detected by the second measuring means2. With respect to the detection of the cross-sectional dimensions ofworkpiece 5, the result which is determined by the first measuring means1 on the basis of the measured data can be checked and a mean value canbe formed between the results determined on the basis of the measureddata by the first and second measuring means.

In accordance with another preferred embodiment, the first measuringmeans 1 and/or the second measuring means 2 includes a laser measuringmeans whose measuring heads are fixedly arranged relative to respectivesupporting means. A deflector device for deflecting the laser measuringbeam is provided for scanning the front surface 3 or the rear surface 4of workpiece 5. Thus the front surface is scanned and the contourimaged, and the cross-sectional dimensions of workpiece 5 are determinedtherefrom, and the distance of the front surfaces 3 and 4 from areference point can be measured. The deflector device for deflecting thelaser measuring beam may, for instance, includes controlled mirrors.

The length of the workpieces can be detected by the device of theinvention for measuring rod shaped workpieces without the workpieceshaving to be aligned in an exact manner and brought into a definedposition in contact with a stop. Moreover, an advantage of the inventionis that apart from the length of the rods the cross-sectional dimensionsof the rod can also be determined, so that storage of the workpieces andsupply of a processing machine with the stored workpieces can becontrolled independently by a control unit.

FIGS. 9, 10, and 11 show a third embodiment of the present invention inwhich essential parts are similar to the first embodiment and thereforeprovided with identical reference numerals.

The device according to the third embodiment has a second guidance 34along which the first guidance 9 is slidably supported and movable. Thesecond guidance 34 is substantially a square profile with guidanceprojections and grooves formed thereon, and a U-shaped slide 37, whichis rigidly connected to the first guidance 9, surrounds the secondguidance 34 and is slidably supported thereon.

As becomes apparent from FIG. 10, the measuring head 7 can thereby beguided past the front surface 3 of workpiece S substantiallyhorizontally at different distance from the supporting surface 11according to different vertical positions of the first guidance 9. Onthe other hand, the measuring head 7 can be guided past the frontsurface 3 in a direction perpendicular to the supporting surface 11 andin parallel with the bearing surface 26 by displacing the first guidancealong the second guidance 34.

To detect the cross-sectional dimensions of workpiece 5, measuring head7 is moved in a first position along the first guidance 9 which islocated at a small distance from the supporting surface 11, so that thelaser measuring beam sweeps over the front surface 3 of workpiece 5substantially horizontally. The first path measuring means 10 exactlydetects at which point there is a workpiece contour at which a first orlast signal change or, in a general manner, a change in the signal levelwill take place upon impingement of the laser measuring beam onworkpiece 5. The control unit links the measured path data, which aredetermined by the first path measuring means 10, with the laser beammeasuring signals of the laser measuring means 7, thereby determiningthe center between the measuring point of the first and last signalchanges, which corresponds to a center perpendicular.

For a second scanning operation the measuring head 7 is positioned inthe previously determined center, so that a laser measuring beam isguided over the front surface 3 of workpiece 5 along the centerperpendicular by displacing the first guidance 9 along the secondguidance 34.

To detect, during the second scanning operation, positions at whichthere is a workpiece contour and at which there will be a first or lastsignal change upon impingement of the laser measuring beam on theworkpiece, a second driving means 35 for effecting the displacement ofthe first guidance 9 along the second guidance 34 is provided with asecond path measuring means 36. The path of displacement of the firstguidance 9, which is determined thereby, corresponds to the height ofworkpiece 5 which, as far as round material is concerned, is diameter Dat the same time.

As shown in FIG. 12, a distinction can be made between flat material andround material by comparing the determined height H with the distance M,W of the measuring points at which the first and last signal changestake place during the first scanning operation in parallel with thesupporting surface 11. If the distance M, W of the measuring points ofthe first and last signal changes during the first scanning operationsis greater than or equal to height H, a flat material is present sinceflat material will always rest with the broad side on the supportingsurface 11.

For increasing the measuring accuracy, in a third scanning operation theguidance 9 is positioned at half the height (1/2)H from the supportingsurface 11 so that measuring head 7 can be moved at that height inparallel with the supporting surface 11. With a flat material, it isthus possible to eliminate any inaccuracy of the width measurementduring the first scanning operation that is possibly caused by therounded edges of workpiece 5. With a round material, it is possible todetermine the diameter D with an increased accuracy through a mean valuebetween height H and the width W which is sensed at half the height(1/2)H during the third scanning operation.

In case workpiece 5 has a complicated and irregular geometry, it ispossible to obtain, through a multitude of scanning operations inparallel with the supporting surface 11 and in parallel with the contactsurface 26, a plurality of measuring data which permit an exactdetermination of the respective profile of workpiece 5 through acomparison with model data which are stored in the storing means in theform of a profiled material data base.

FIG. 13 shows a fourth embodiment of a device for measuring dimensionsof workpieces. A workpiece 101 is disposed on a supporting means 102which forms part of a cross conveying means (not shown in more detail).As becomes apparent from FIG. 14, the cross conveying means includesconveying chain belts 125 which are driven by a pinion 126 and a drive(not shown). The conveying chain belts 125 form, together withsupporting bolts 127, a supporting surface on which workpiece 101 issupported. The conveying chain belts 125 have pushing bolts 128 attachedthereto, which form a bearing surface on which workpiece 101 is roughlyaligned during cross conveyance on the cross conveying means. Theconveying chain belts 125 and the pushing bolts 128 are closely arrangedfor short workpieces, such as short rods or remaining rods, preferablytowards one side of the cross conveying means in the longitudinaldirection of the workpiece, and have an increasing distance from oneanother towards the opposite end of the cross conveying means.

The cross conveying means is part of a conveyor system by whichworkpieces, in particular rods, are conveyed from a storage place to aprocessing machine and, after having been processed, for instance by asaw, are conveyed back to the storage place at least partly, i.e. as theremaining pieces which were cut off by the saw.

To detect the geometry of the workpiece, there is provided a measuringmeans which is generally designated by reference numeral 103. Themeasuring means 103 includes a sensor means 104 which is movablerelative to the workpiece 101 resting on the supporting means 102 so asto scan the surfaces of workpiece 101. In the embodiment the sensormeans 104 is formed by a laser sensor which includes a measuring head105 that emits a laser beam 129 and scans the workpiece surfacestherewith.

The measuring head 105 is movably supported on a guiding device which isgenerally designated by reference numeral 106. The guiding device 106has a longitudinal guidance 109 which spans the supporting means 102 inthe longitudinal direction thereof, i.e. in the longitudinal directionof workpiece 101 and is fixedly attached to supporting props 130 which,in turn, are anchored at both sides of the supporting means 102 in asuitable manner.

As shown in FIG. 14, guiding device 106 further includes two linearguidances 112, 114 which are displaceably supported on the longitudinalguidance 109 and connected to each other via a cross slide 110. A firstone of the two linear guidances, which is designated by referencenumeral 112, has a guiding slide 131 fixedly attached thereto, andmovably supported on the longitudinal guidance 109. The guiding slide131 is formed by a substantially rectangular profile and consequentlymovably guides the first linear guidance 112 along longitudinal guidance109.

As becomes apparent from FIG. 13, the first linear guidance 112 ismovable by a driving means 107 along the longitudinal guidance 109. Thedriving means 107 includes a toothed belt drive and an encoder coupledto the toothed belt for exactly detecting the position of the linearguidance 112 relative to the longitudinal guidance 109.

As becomes apparent from FIG. 14, cross slide 110 is supported on thefirst linear guidance 112 for moving along the first linear guidance 112in a direction transverse to the longitudinal direction of workpiece101. A driving means 132 is connected via a toothed belt drive to crossslide 110 to move the same in accordance with a control signal. Anencoder 115 is coupled to driving means 132 to sense the exact positionof cross slide 110 relative to the first linear guidance 112.

In a direction perpendicular to the longitudinal direction of the firstlinear guidance 112, the cross slide 110 slidably guides a second linearguidance 113 which is thus displaceable both horizontal, i.e. togetherwith cross slide 110 along the first linear guidance 112, andvertically. For vertical displacement of the second linear guidance 113,another driving means 114 is provided which includes a toothed beltdrive and an encoder 108 coupled thereto for detecting the exactposition of the second linear guidance 113 relative to cross slide 110.

Apart from the horizontal and vertical movability in a planeperpendicular to the longitudinal direction of the supporting means 102,i.e. the longitudinal axis of the rod shaped workpiece 101, the secondlinear guidance 113 is also displaceable due to the movable support ofthe first linear guidance 112 in parallel with the longitudinal axis ofworkpiece 101, which axis is perpendicular to the plane of drawing inFIG. 14. Therefore the measuring head 105 of laser sensor 104 which isarranged on the lower end of the second linear guidance 113 is movablealong any three-dimensional curve, especially along straight linesoriented in any direction, and is guidable along the surfaces ofworkpiece 101.

As shown in FIGS. 13 and 14 and in the schematic diagram of FIG. 18, themeasuring head 105 is connected via a swinging means 119 to a lower endof the second linear guidance 113. The swinging means 119 allows andcauses the measuring head 105 to swing relative to the second linearguidance 113 in such a manner that the laser beam 129 exiting from themeasuring head 105 impinges horizontally and vertically on the workpiecesurfaces to be respectively scanned.

As becomes apparent from FIG. 18, the measuring means 103 is especiallydistinguished in that the measuring head 105 of sensor means 104 can bemoved and also swung in three axes, so that both a front surface 132(FIG. 13) and a lateral surface 133 (FIG. 14) of workpiece 101 can bescanned by the single measuring head 105.

The workpiece 101 is measured in compliance with a suitable controlsystem according to which measuring head 105 is guided past the varioussurfaces of workpiece 101.

An important aspect with respect to the automated storage and removal ofworkpieces is the sensing of the cross-sectional geometry of workpieces101. To this end, sensor means 104 is first positioned in a basicposition at an end of supporting means 102 outside a collision area withworkpiece 101, i.e. the first linear guidance 112 is moved along thelongitudinal guidance 109 to such an extent in the longitudinaldirection, which is marked in FIG. 18 as the X direction, that measuringhead 105 can be guided by in front of the front surface 132 of workpiece101.

Then, swinging means 119 causes measuring head 105 to swing into anangular position perpendicular to the front surface 132, i.e. in such amanner that the laser beam 129 exiting from measuring head 105 is inparallel with the longitudinal direction X.

In a subsequent step, measuring head 105 is guided past the frontsurface 132 of the workpiece in parallel with the supporting surface onwhich workpiece 101 rests. That is, cross slide 110 is moved along thefirst linear guidance 112 in the Y direction (FIG. 18) with the secondlinear guidance 113 supported thereon. As a result, the laser beam 129will impinge on the front surface 132 of the workpiece. As becomesapparent from FIG. 20, this will lead to a change in the signal level oflaser sensor 104 when measuring head 105 is guided by. Hence, a firstsignal change means the beginning of a workpiece contour whereas a lastsignal change corresponding to a drop in signal level marks the end ofthe contour. As long as measuring head 105 is guided past workpiece 101,a corresponding path measuring device which is formed by encoder 115 incase of a displacement in the Y direction senses the respective positionof the measuring head 105 in which a change in the signal level takesplace.

The detected and measured path data are linked with the laser beammeasuring signals of laser sensor 104 in a calculation unit of a controlunit (not shown in the figures). In this way the control unit firstcalculates the center (in the Y direction) of the front surface 132 ofthe workpiece.

In the next step, the measuring head 105 is guided vertically past thefront surface 132 of the workpiece through the previously determinedcenter by the second linear guidance 113 being moved relative to thecross slide 110, which is fixed in that case. On the basis of signalsfrom laser sensors 104 in combination with data from the encoder 108showing the position of the second linear guidance 113, the workpieceheight H can be calculated by the control unit in this step.

Although in the embodiment shown in FIGS. 13 and 14 the second linearguidance 113 is moved relative to the cross slide 110, it is alsopossible to make the second linear guidance 113 stationary relative toslide 110 and to move the sensor means 104 together with the swingingmeans 119 along the second linear guidance 113. Such a development ofthe linear guidances is diagrammatically shown in FIG. 18. By analogy,it is of course also possible to ensure the movability of the guidingdevice in the Y direction through a corresponding movability of thefirst linear guidance 112 relative to the longitudinal guidance 109. Theguiding slide 131 is provided here with a cross slide for slidablysupporting the guidance 112.

After the height H of the workpiece has been determined, the measuringhead 5 is guided past the front surface 132 of the workpiece at half theworkpiece height H/2 in the Y direction a second time so as to sense awidth W of the workpiece. The width W is calculated according to theabove-described manner by the control unit on the basis of the laserbeam measuring signals in combination with the measured path data ofencoder 115.

It should be noted that in the case of hollow material, the wallthickness can also be calculated by scanning the front surface 132 ofthe workpiece.

Moreover, the control unit can make distinction between round and flatmaterials in accordance with an evaluating logic stored in a memorymeans, as shown in FIG. 20. That is, in contrast to flat material, thecorner portion provided between the support surface, which is formed bythe conveying chain belts 125, and the bearing surface, which is formedby the pushing bolts 128, are not filled with material in the case ofround material. For instance, when the measuring head 105 is guided pastthe front surface 132 of the workpiece horizontally in the Y directionat a level of slightly more or less than half the workpiece height fromthe support surface, beginning from the bearing surface of the pushingbolts 128, a first signal change takes place only at a certain distancefrom the bearing surface of pushing bolts 128. The control unit willtherefore recognize that workpiece 101 is a round material. Other pathsof movement are possible for making a distinction between round materialand flat material.

Furthermore, a multitude of measured data that permit an exactdetermination of the respective profile of the workpiece by comparisonwith model data stored in the memory means in the form of a profiledmaterial data base can be obtained for a workpiece of a complicated andirregular geometry through a plurality of scanning operations inparallel with the supporting surface, i.e. in the Y direction, and inparallel with the bearing surface, i.e. in the Z direction.

After sensor means 104 has sensed the cross section of workpiece 101,the swinging means 119 swings the measuring head 105 into the Zdirection, so that the laser beam 129 exiting from measuring head 105 isin parallel with the Z direction according to FIG. 18. Further the firstlinear guidance 112 and the second linear guidance 113 position themeasuring head 105 in the Y direction centrally above the workpiece 101.The first linear guidance 112 is then moved along the longitudinalguidance 109 in the X direction, and the measuring head 105 is thenguided in the described position in the longitudinal direction overworkpiece 101. During displacement in the X direction, the encodercoupled to the toothed belt drive of driving means 107 detects thepositions of the measuring head 105 in which a first signal change and alast signal change take place. The control unit calculates length L0 ofworkpiece 101 from the corresponding laser beam measuring signals andmeasured path data.

During displacement in the X direction, the respective distance ofmeasuring head 105 from the surface of workpiece 101 is measured atfixed intervals so as to determine the straightness and an inclinedposition of the workpiece in the X-Z plane. To this end, the controlunit links the respectively detected distances between the measuringhead 105 and the lateral surface of the workpiece 101, with theassociated measured path data which are determined by the encodercoupled to the driving means 107, and calculates, as shown in FIG. 21,the angular position and the curvature of the scanned surface line ofthe workpiece which correspond to the inclined position and thestraightness of the workpiece in the X-Z plane. It should be noted thatfor such a measurement of the straightness of workpiece 101, it isespecially the portal-like structure of the guiding device 106 with thelongitudinal guidance 109 and the two linear guidances 112 and 113 aswell as the encoder directly coupled to the toothed belt drives fordirect path measurement that are of special advantage to a high accuracyof the measurements.

In a next step, swinging means 119 swings measuring head 105 into the Ydirection in such a manner that the laser beam 129 exiting frommeasuring head 105 extends in the Y direction, and the first linearguidance 112 and the second linear guidance 113 position the measuringhead 105 laterally of workpiece 101 at half the height of workpiece 101.The measuring head 105 is guided in this position in the X directionpast workpiece 101 to detect straightness and inclined position of therod in the X-Y plane according to the above-described manner.

As shown in FIGS. 15 and 16, the swinging means 119 for swinging themeasuring head 105 includes two series connected swinging members 120and 121 which are each swingable by 90° about a swinging axis γ and δbetween two positions. A first swinging member 120 is fixedly connectedby means of a holding bracket 134 to a lower end of the second linearguidance 113. A first adjusting ring 135 of the first adjusting member120 is rotatable by 90° about the swinging axis γ. A second adjustingmember 121 is rigidly connected with the aid of a holding bracket 136 tothe first adjusting member 135, so that the second adjusting member 121can be swung by the first adjusting member 120 around swinging axis γ.The second adjusting member 121 possesses a second adjusting ring 137which is rotatable by 90° about the axis δ. The ring 137 has themeasuring head 105 attached thereto via a measuring head holding means138. The measuring head 105 is swingable about two axes γ, δ due to theseries connection of the two swinging members 120 and 121, which can forinstance be operated by compressed air or also by rotary field magnets.This solution is especially simple, but nevertheless ensures adequateaccuracy. However, it is also possible to support measuring head 105such that it is swingable in three axes.

As compared with FIGS. 15 and 16, FIGS. 17A, 17B, and 17C show analternative embodiment of the swinging means 119 wherein two seriesconnected swinging members 220 and 221 form a pivot/swing joint. A firstswinging member 220 is supported on a lateral surface of a holding plate139, which is rigidly connected to a lower end of the second linearguidance 113, so as to be rotatable about a horizontal axis A. A secondswinging member 221 is supported on an inclined surface 220a of thefirst swinging member 220 so as to be rotatable about an axis B makingan angle of 45° with the axis A. With this arrangement, in the positionof the swinging members shown in FIG. 17A, the laser beam 129 isdirected in the vertical direction. When the first swinging member 220is rotated through 90° from the foregoing position, the laser beam 129is rotated and directed to a first horizontal direction perpendicular tothe axis A as shown in FIG. 17B. On the other hand, when the secondswinging member 221 is rotated through 180° from the foregoing position,the laser beam 29 is rotated and directed to the second horizontalposition parallel to the axis A as shown in FIG. 17C.

With the above-described embodiment of an inventive device, it ispossible to measure workpieces of very different sizes with a highaccuracy. For instance, as outlined in FIG. 18, rods with a length of800 mm up to a maximum length of 6600 mm can be placed on the supportingmeans 102 and measured with a maximum error of 1 mm. The supportinglength d is about 6600 mm. Height H of the workpiece and width W thereofcan each amount up to 320 mm. It is here of particular advantage thatthe workpiece on the supporting means 102 need not be brought into adefined position, specifically into contact with a stop, but a frontsurface of the workpiece has just to be positioned within a tolerancerange of, for instance, 100 mm. A cumbersome displacement of theworkpiece on the supporting surface is thus not necessary.

Apart from the above-described embodiment according to FIGS. 13 and 14with the two linear guidances 112, 113 connected by a cross slide 110,it is also possible, as shown in FIG. 19, to provide a pivotal armguidance 116 for guiding the measuring head 105 with at least twopivotal arms 117 and 118 in the plane perpendicular to the longitudinaldirection of workpiece 101, i.e., in the plane perpendicular to the Xdirection according to FIG. 19. The pivotal arm guidance 116 is slidablyguided on the longitudinal guidance 109 in the longitudinal direction,i.e. in the X direction, by a slide 140 which, similar to guidance slide131 (see FIG. 14), is slidably supported on the longitudinal guidance109. A first pivotal arm 117 is pivotally supported relative to theslide 140 about a first axis parallel to the longitudinal direction ofthe longitudinal guidance 109 and pivotal by a driving means (notshown). A second pivotal arm 118 is supported on the first pivotal arm117 and adapted to be pivotal relative thereto about a second axis alsoin parallel with the X axis. A driving means for pivoting the secondpivotal arm is not shown, nor are there shown path measuring sensorscoupled to the drive for detecting the position of the measuring headwhich is arranged on the second pivotal arm 118. The measuring head 105is connected to a lower end of the second pivotal arm 118 via a swingingmeans 119, which corresponds to one of the above-described embodiments,to swingably support the measuring head 105 relative to the secondpivotal arm 118.

The pivotal arm guidance 116, which substantially corresponds to apivotal arm robot, makes it possible, together with the movable supporton the longitudinal guidance 109 and the swinging means 119, to guidethe measuring head 105 past the surface of workpiece 101 along differentstraight lines oriented in any direction. The cross section, length andstraightness of the workpiece are detected in the manner as describedfor the embodiment illustrated in FIG. 18, so that a repeated detailedexplanation is omitted.

The above-described embodiments of a device according to the inventionfor measuring workpieces are, inter alia, distinguished from prior artsby the fact that both the cross section of the workpiece and the lengthof the workpiece as well as its straightness can be detected by a singlesensor means. It should once again be pointed out that it is alsopossible to arrange several measuring heads on the guiding device, themeasuring heads being oriented accordingly for different scanningoperations. A swinging means can be dispensed with in such a case.

In the above-mentioned embodiment, the measuring of the workpiece wasexplained in combination with a cross conveying means through which theworkpiece is supplied to a roller conveyor of a processing machine, suchas a sawing machine. As for the location of the arrangement of themeasuring means, this is of course only an example. The measurement can,for instance, also be performed within the roller conveyor itself, i.e.after the workpiece has been supplied thereto, or within the materialstore, for instance a cantilever type store (shelf type store) for rodmaterial, or outside the material store to measure workpieces to besupplied to the material store.

We claim:
 1. Device for measuring dimensions of a rod-shaped workpiece,comprising:supporting means for supporting and substantially aligningthe workpiece, said supporting means including a supporting surface anda bearing surface, and sensor means for detecting dimensions of one of afront surface and a rear surface of the workpiece; wherein said sensormeans comprises:a guide swingable about an axis substantially parallelto an intersection axis of the supporting surface and the bearingsurface, a measuring carriage slidably supported on the guide, a pathmeasuring device for detecting a position of the measuring carriage onthe guide, and a measuring head supported on the measuring carriage fordetecting a contour of said one of said front surface and said rearsurface of the workpiece.
 2. Device of claim 1, further comprisingcontrol means connected to the path measuring device and the measuringhead for determining a cross-sectional shape of the workpiece on thebasis of signals from the path measuring device and the measuring head,wherein said control means determines that the cross-sectional shape ofthe workpiece is a circle when a length of a path between the contour ofsaid one of said front surface and said rear surface of said workpieceand the intersection axis is substantially greater than zero.
 3. Deviceof claim 1, further comprising detecting means for detecting the lengthof the workpiece.
 4. Device of claim 1, further comprising driving meansfor driving said measuring head.
 5. Device of claim 1, wherein saidmeasuring head includes a laser sensor.
 6. Device of claim 5, furthercomprising an evaluating unit for linking measured path data from saidpath measuring device with laser beam measuring signals from said lasersensor, whereby to determine dimensions of a cross-sectional shape ofthe workpiece.
 7. Device of claim 1, wherein said sensor means includesa laser measuring device and a deflector device for deflecting a lasermeasurement beam, whereby to scan said one of said front surface andsaid rear surface of said workpiece.
 8. Device of claim 1, wherein saidsensor means includes a laser measuring device, said measuring headcomprising a laser measurement head, said device further comprisingdriving means for driving said laser measurement head during a laserscanning operation.
 9. Device of claim 1, wherein said guide isswingable between a first position and a second position, and whereinsaid measuring carriage is drivable in parallel with a front diagonalsurface of said workpiece when said guide is in said first position, andwherein said measuring carriage is drivable in parallel with saidsupporting surface of said supporting means when said guide is in saidsecond position.
 10. Device of claim 9, wherein said measuring headincludes a laser sensor, said device further comprising an evaluatingunit for linking measured path data from said path measuring device withlaser beam measuring signals from said laser sensor, whereby todetermine dimensions of a cross-sectional shape of the workpiece. 11.Device of claim 1, further comprising driving means for driving saidmeasuring carriage, said driving means including a toothed belt driveand an encoder coupled to said toothed belt drive for path measurement.12. Device of claim 11, wherein said measuring head includes a lasermeasuring device and a deflector device for deflecting a lasermeasurement beam, whereby to scan said one of said front surface andsaid rear surface of said workpiece.
 13. Device of claim 1, wherein saidsupporting means comprises a conveying unit for cross-conveying saidworkpiece, said conveying unit including at least one conveying chainbelt and at least one pushing bolt attached thereto, said at least oneconveying chain belt forming said supporting surface of said supportingmeans and said at least one pushing bolt forming said bearing surface ofsaid supporting means.
 14. Device of claim 1, wherein said sensor meansincludes a first measuring unit for detecting a distance between a frontsurface of said workpiece and a reference point, and a second measuringunit for detecting a distance between a rear surface of said workpieceand said reference point.
 15. Device of claim 14, wherein said secondmeasuring unit includes an additional measuring carriage and a tactilesensor disposed on said additional measuring carriage.
 16. Device ofclaim 14, wherein said supporting means comprises a conveying unit forcross-conveying said workpiece, said conveying unit including at leastone conveying chain belt and at least one pushing bolt attached thereto,said at least one conveying chain belt forming said supporting surfaceof said supporting means and said at least one pushing bolt forming saidbearing surface of said supporting means.
 17. Device of claim 15,wherein said additional measuring carriage is supported slidably andsubstantially in parallel with an intersection axis of said supportingsurface and said bearing surface of said supporting means, said devicefurther comprising driving means for driving said additional measuringcarriage toward the rear surface of said workpiece, and an additionalpath measuring device for detecting a position of said additionalmeasuring carriage.